1. Field of the Invention
This invention relates to window assemblies, and more specifically to window assemblies that are used in buildings located in seismic zones or in buildings designed to withstand a blast.
2. Description of the Related Art
Window assemblies in buildings are commonly installed by fastening, bolting or welding the window frame to the building's main structure.
Seismic movement creates story drift in buildings, which is the lateral displacement of one level relative to the level below or above. This causes lateral movement to the building main structure and the attached window frame.
The lateral movement of the window frame causes it to crush the glass panes in the window. Without adequate clearance space for the movement, the glass in window might break during a strong earthquake. The chance for glass breakage is greater in larger and taller glass panes, because they are affected by greater lateral displacement. However, large glass panes are highly desirable in many facilities including air traffic control tower cabs.